Tibial Spine (Intercondylar Eminence) Fracture Fixation

Surgical Indications

Absolute Indications

• Type III (completely displaced) and Type IV (comminuted) fractures
• Type II fractures with residual displacement greater than 2 mm after closed reduction in extension
• Any fracture with interposed soft tissue preventing anatomic reduction
• Associated meniscal tear or osteochondral injury requiring surgery

Relative Indications

• Type II fracture in a high-demand athlete or patient unwilling to accept 6-8 weeks in cast
• Skeletally immature patient with Type II fracture where cast treatment risks compliance issues
• Delayed presentation with partial healing and displacement

Contraindications

Absolute:

• Active infection
• Severe soft-tissue swelling precluding arthroscopy (consider staged procedure)
• Medical comorbidities precluding anaesthesia

Relative:

• Type I nondisplaced fracture (treat with extension cast or brace)
• Type II fracture that reduces anatomically with less than 2 mm residual displacement (may trial non-operative)

Meyers and McKeever Classification

Evidence for Fixation Threshold

• Residual displacement greater than 2 mm after closed reduction correlates with extension loss and ACL laxity in multiple series.
• Anatomic reduction (less than 1 mm step-off) restores ACL footprint tension and reduces risk of arthrofibrosis.
• In skeletally immature patients, physeal-sparing fixation yields excellent outcomes with minimal growth disturbance when performed correctly.

Evidence Summary

Relevant Anatomy of the Tibial Spine

ACL Footprint and Tibial Spine Morphology

• The ACL tibial footprint occupies the anteromedial aspect of the intercondylar eminence.
• The tibial spine (intercondylar eminence) comprises two tubercles: medial and lateral; the ACL attaches to the medial tubercle and the anterior slope.
• The footprint measures approximately 10-12 mm in anteroposterior dimension and 8-10 mm mediolaterally in adults.
• In children the footprint is proportionally larger relative to the plateau and lies closer to the physis.

Relationship to the Proximal Tibial Physis

• The proximal tibial physis lies 3-5 mm posterior and distal to the posterior margin of the ACL footprint.
• The physis is undulating and slopes proximally in the midline; any tunnel or screw directed posteriorly risks physeal penetration.
• In the skeletally immature knee the physis must be visualised on pre-operative MRI or intra-operative fluoroscopy to confirm all fixation remains epiphyseal.

Intermeniscal Ligament and Meniscal Anatomy

• The intermeniscal (transverse geniculate) ligament crosses the anterior intercondylar area immediately anterior to the tibial spine.
• In greater than 50 percent of displaced tibial spine fractures the ligament or anterior horn of the medial meniscus becomes interposed between the fragment and the fracture bed.
• The anterior horn of the medial meniscus may also flip into the crater; failure to clear these structures prevents anatomic reduction.

Neurovascular Structures at Risk

• The popliteal artery lies 1-2 cm posterior to the tibial plateau at the level of the spine; posterior perforation with a drill or guide pin risks vascular injury.
• The common peroneal nerve is protected laterally but can be injured with aggressive lateral compartment retraction.
• The infrapatellar branch of the saphenous nerve is at risk with anteromedial portal placement.

Notch Anatomy and Potential for Impingement

• The intercondylar notch width averages 18-22 mm; a prominent reduced tibial spine fragment can cause notch impingement and extension block.
• Notchplasty (limited resection of the anterior notch roof) is indicated when the reduced fragment remains proud greater than 2 mm.

Positioning and Preparation

Patient position: Supine on radiolucent table with thigh tourniquet. Leg holder or post allows 90-degree flexion and full extension. Contralateral leg in well-leg holder. Prepare and drape the entire limb from toes to groin.

Anaesthesia: General anaesthesia with optional regional block (adductor canal or femoral nerve catheter) for post-operative analgesia. Spinal anaesthesia is acceptable in adolescents.

Equipment: 30-degree and 70-degree arthroscopes, standard knee instrumentation, ACL guide, 2.4 mm and 4.5 mm cannulated drills, high-strength suture (FiberWire or equivalent), 4.0 or 4.5 mm cannulated screws with washers if screw fixation chosen, C-arm fluoroscopy.

Consent: Discuss risk of arthrofibrosis (10-25 percent), residual ACL laxity (5-10 percent), growth disturbance (less than 1 percent with physeal-sparing technique), hardware prominence requiring removal, and infection (less than 1 percent).

Arthroscopic Reduction and Fixation — Step-by-Step

Step 1: Diagnostic Arthroscopy and Portal Placement

Establish standard anterolateral and anteromedial portals. Perform systematic diagnostic arthroscopy of patellofemoral joint, medial and lateral gutters, and both compartments. Document and address any meniscal or chondral injuries first.

Inspect the tibial spine fracture. Identify the intermeniscal ligament and anterior horn of medial meniscus. Use a probe to determine whether soft tissue is interposed within the fracture crater.

Step 2: Fracture Debridement and Preparation

Use a shaver and curette to remove hematoma and fibrous tissue from the fracture bed. Freshen the fragment edges and the crater walls to bleeding cancellous bone. Confirm that the intermeniscal ligament and meniscus are completely cleared from the interface.

Measure the fragment size and assess comminution. This determines fixation method: single large fragment (greater than 1 cm) favours cannulated screw; comminuted or small fragment favours suture bridge.

Step 3: Fracture Reduction

Flex the knee to 30-45 degrees. Use an ACL probe or elevator to reduce the fragment under direct vision. Apply posterior drawer force to the tibia while holding the fragment reduced. Confirm anatomic reduction with the fragment flush to the surrounding plateau on both anteroposterior and lateral fluoroscopic views.

If reduction cannot be achieved, re-inspect for residual interposed tissue or incarcerated meniscus.

Step 4: Fixation — Suture Bridge Technique (Physeal-Sparing)

This is the preferred technique for comminuted fragments and all skeletally immature patients.

Create a 2 cm longitudinal incision 3 cm distal to the tibial tuberosity, medial to midline. Drill two 2.4 mm tunnels from the anterior tibial cortex exiting in the ACL footprint on either side of the reduced fragment. Pass a suture passer or Hewson suture passer through each tunnel.

Pass two or three high-strength sutures through the base of the ACL just above the fragment using a suture lasso or bird-beak. Retrieve the sutures through the tibial tunnels. Tie the sutures over a 2 cm bone bridge on the anterior tibia with the knee in full extension.

Confirm reduction and stability with arthroscopic visualisation and fluoroscopy. Cycle the knee through full range of motion to verify no loss of fixation.

Step 5: Fixation — Cannulated Screw Technique (Skeletally Mature)

Indicated for large single fragments in patients with closed physis.

Reduce the fragment as above. Insert a guide wire from the anteromedial tibia through the fragment under fluoroscopic guidance, avoiding the physis. Confirm wire position on anteroposterior and lateral views.

Drill with a 4.0 mm cannulated drill over the wire, measure length, and insert a 4.5 mm partially threaded cannulated screw with washer. The screw should engage the posterior cortex but not protrude excessively.

Perform notchplasty if the reduced fragment remains proud greater than 2 mm.

Step 6: Final Assessment and Closure

Confirm anatomic reduction, stable fixation, and full extension under direct vision and fluoroscopy. Irrigate the joint. Close portals with absorbable suture. Apply sterile dressing and extension brace.

Post-operative Protocol

Immediate (Day 0-14)

• Brace: Locked in full extension for first 2 weeks (suture fixation) or 4 weeks (screw fixation)
• Weight-bearing: Toe-touch only for 4-6 weeks; progress to partial then full as radiographic healing confirms
• Motion: Passive extension to zero degrees immediately; active-assisted flexion begins at 2 weeks; goal full ROM by 6-8 weeks
• Analgesia: Multimodal including regional catheter if placed; paracetamol, NSAIDs, limited opioids
• Elevation and cryotherapy: 48-72 hours to control swelling

Early Rehabilitation (Weeks 2-6)

• Prone hangs and heel props for extension emphasis
• Quadriceps sets and straight-leg raises in brace
• Patellar mobilisation to prevent patellar tendon contracture
• Hamstring and calf stretching
• Transition to functional brace at 2-4 weeks

Late Rehabilitation (Weeks 6-12)

• Progressive resistance exercises
• Stationary cycling when ROM allows
• Proprioceptive training
• Return to running at 3-4 months if radiographic union and full painless ROM
• Return to sport at 6-9 months after isokinetic strength testing and hop testing

Special Considerations in Children

• Compliance with brace and non-weight-bearing is challenging; involve parents and consider removable cast or hinged brace with lock
• Serial radiographs at 2, 6, and 12 weeks to confirm maintenance of reduction and physeal integrity
• Follow with scanograms until skeletal maturity if any physeal concern

Outcomes

• Anatomic reduction with stable fixation yields greater than 90 percent good to excellent results (Lysholm greater than 90).
• Residual extension loss greater than 5 degrees occurs in 5-10 percent despite optimal care.
• Return to pre-injury sport level is 80-90 percent in adolescents with anatomic reduction.
• Long-term ACL laxity is present in 10-15 percent but symptomatic instability requiring reconstruction is uncommon (less than 5 percent) when reduction is anatomic.